High power density tubes

A more recent development in high power density large-scale tubular SOFCs is that of flat tubes, which consist of a tube with two flat, parallel sides, and two rounded sides, with cross-connected current paths connecting the two flat faces of the tubes through the interior to minimize the length of the current path, as shown schematically in Figure 6.6 [48],... 

FIGURE 6.6 High power density (HPD) SOFC, consisting of a flattened tube with two flat faces. The vertical struts between the two flat faces provide shorter paths for the electronic current collection, eliminating the need for all of the electronic current to travel around the circumference of the cathode, as in the standard tubular cell design shown in Figure 6.5 [48], Reprinted from [48] with permission from Elsevier. 

Lu, Y., Schaefer, L. and Li, P. (2005) Numerical study of a flat tube high power density solid oxide fuel cell. Part I Heat/mass transfer and fluid flow, Journal of Power Sources 140, 331-339. 

Integrated planar SOFC and flat-tube high-power density designs... 

Fig. 2.4 Mediators can achieve high power densities in MFCs. (A) Solvent extracts from an MFC showing characteristic biue-green coiors, typicai of phenazines such as pyocyanin and phenazine-1-carboxamide produced by bacteria such as Pseudomonas aeruginosa] (B) a recirculation tube stained blue, likely by adsorbed mediators (C) cation exchange membrane of 4 anodic chambers containing P. aeruginosa that produced different phenazines the mediators partially sorbed onto the membrane. [Photographs by K. Rabaey.]...

Optical second-harmonic generation (SHG) has recently emerged as a powerful surface probe [95, 96]. Second harmonic generation has long been used to produce frequency doublers from noncentrosymmetric crystals. As a surface probe, SHG can be caused by the break in symmetry at the interface between two centrosymmetric media. A high-powered pulsed laser is focused at an angle of incidence from 30 to 70° onto the sample at a power density of 10 to 10 W/cm. The harmonic is observed in reflection or transmission at twice the incident frequency with a photomultiplier tube. 

The maximum power of a conventional X-ray tube is 2.4 kW for broad focus (approx.. 2x 12 mm focal spot size). Modern rotating anodes consume 18 kW and deliver fine focus (approx.. 0.1 x 1 mm focal spot size). Most important for high intensity is not the power consumption, but the product of focal spot power density and focal spot size or, more accurately, the flux on the sample measured in photons/s (cf. Sect. 7.6). 

---